/*
	AP_MotorsMatrix.cpp - ArduCopter motors library
	Code by RandyMackay. DIYDrones.com

	This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
*/

#include "AP_MotorsMatrix.h"

// Init
void AP_MotorsMatrix::Init()
{
	int8_t i;

    // call parent Init function to set-up throttle curve
    AP_Motors::Init();

    // setup the motors
    setup_motors();

	// double check that opposite motor definitions are ok
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( opposite_motor[i] <= 0 || opposite_motor[i] >= AP_MOTORS_MAX_NUM_MOTORS || !motor_enabled[opposite_motor[i]] )
			opposite_motor[i] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
	}

	// enable fast channels or instant pwm
	set_update_rate(_speed_hz);
}

// set update rate to motors - a value in hertz or AP_MOTORS_SPEED_INSTANT_PWM for instant pwm
void AP_MotorsMatrix::set_update_rate( uint16_t speed_hz )
{
	uint32_t fast_channel_mask = 0;
	int8_t i;

	// record requested speed
	_speed_hz = speed_hz;

	// check each enabled motor
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( motor_enabled[i] ) {
			// set-up fast channel mask
			fast_channel_mask |= _BV(_motor_to_channel_map[i]);	// add to fast channel map
		}
	}

	// enable fast channels
		_rc->SetFastOutputChannels(fast_channel_mask, _speed_hz);
}

// set frame orientation (normally + or X)
void AP_MotorsMatrix::set_frame_orientation( uint8_t new_orientation )
{
	// return if nothing has changed
	if( new_orientation == _frame_orientation ) {
		return;
	}

	// call parent
	AP_Motors::set_frame_orientation( new_orientation );

	// setup the motors
	setup_motors();

	// enable fast channels or instant pwm
	set_update_rate(_speed_hz);
}

// enable - starts allowing signals to be sent to motors
void AP_MotorsMatrix::enable()
{
	int8_t i;

	// enable output channels
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( motor_enabled[i] ) {
			_rc->enable_out(_motor_to_channel_map[i]);
		}
	}
}

// output_min - sends minimum values out to the motors
void AP_MotorsMatrix::output_min()
{
	int8_t i;

	// fill the motor_out[] array for HIL use and send minimum value to each motor
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( motor_enabled[i] ) {
			motor_out[i] = _rc_throttle->radio_min;
			_rc->OutputCh(_motor_to_channel_map[i], motor_out[i]);
		}
    }
}

// output_armed - sends commands to the motors
void AP_MotorsMatrix::output_armed()
{
    int8_t i;
    int16_t out_min = _rc_throttle->radio_min;
    int16_t out_max = _rc_throttle->radio_max;
    int16_t rc_yaw_constrained_pwm;
    int16_t rc_yaw_excess;
    int16_t upper_margin, lower_margin;
    int16_t motor_adjustment = 0;
    int16_t yaw_to_execute = 0;

    // initialize reached_limit flag
    _reached_limit = AP_MOTOR_NO_LIMITS_REACHED;

    // Throttle is 0 to 1000 only
    _rc_throttle->servo_out = constrain(_rc_throttle->servo_out, 0, _max_throttle);

    // capture desired roll, pitch, yaw and throttle from receiver
    _rc_roll->calc_pwm();
    _rc_pitch->calc_pwm();
    _rc_throttle->calc_pwm();
    _rc_yaw->calc_pwm();

    // if we are not sending a throttle output, we cut the motors
    if(_rc_throttle->servo_out == 0) {
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i]    = _rc_throttle->radio_min;
            }
        }
        // if we have any roll, pitch or yaw input then it's breaching the limit
        if( _rc_roll->pwm_out != 0 || _rc_pitch->pwm_out != 0 ) {
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT;
        }
        if( _rc_yaw->pwm_out != 0 ) {
            _reached_limit |= AP_MOTOR_YAW_LIMIT;
        }
    } else {    // non-zero throttle

        out_min = _rc_throttle->radio_min + _min_throttle;

        // initialise rc_yaw_contrained_pwm that we will certainly output and rc_yaw_excess that we will do on best-efforts basis.
        // Note: these calculations and many others below depend upon _yaw_factors always being 0, -1 or 1.
        if( _rc_yaw->pwm_out < -AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM ) {
            rc_yaw_constrained_pwm = -AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
            rc_yaw_excess = _rc_yaw->pwm_out+AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
        }else if( _rc_yaw->pwm_out > AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM ) {
            rc_yaw_constrained_pwm = AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
            rc_yaw_excess = _rc_yaw->pwm_out-AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
        }else{
            rc_yaw_constrained_pwm = _rc_yaw->pwm_out;
            rc_yaw_excess = 0;
        }

        // initialise upper and lower margins
        upper_margin = lower_margin = out_max - out_min;

        // add roll, pitch, throttle and constrained yaw for each motor
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i] = _rc_throttle->radio_out +
                               _rc_roll->pwm_out * _roll_factor[i] +
                               _rc_pitch->pwm_out * _pitch_factor[i] +
                               rc_yaw_constrained_pwm * _yaw_factor[i];

                // calculate remaining room between fastest running motor and top of pwm range
                if( out_max - motor_out[i] < upper_margin) {
                    upper_margin = out_max - motor_out[i];
                }
                // calculate remaining room between slowest running motor and bottom of pwm range
                if( motor_out[i] - out_min < lower_margin ) {
                    lower_margin = motor_out[i] - out_min;
                }
            }
        }

        // if motors are running too fast and we have enough room below, lower overall throttle
        if( upper_margin < 0 || lower_margin < 0 ) {

            // calculate throttle adjustment that equalizes upper and lower margins.  We will never push the throttle beyond this point
            motor_adjustment = (upper_margin - lower_margin) / 2;      // i.e. if overflowed by 20 on top, 30 on bottom, upper_margin = -20, lower_margin = -30.  will adjust motors -5.

            // if we have overflowed on the top, reduce but no more than to the mid point
            if( upper_margin < 0 ) {
                motor_adjustment = max(upper_margin, motor_adjustment);
            }

            // if we have underflowed on the bottom, increase throttle but no more than to the mid point
            if( lower_margin < 0 ) {
                motor_adjustment = min(-lower_margin, motor_adjustment);
            }
        }

        // move throttle up or down to to pull within tolerance
        if( motor_adjustment != 0 ) {
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] ) {
                    motor_out[i] += motor_adjustment;
                }
            }

            // we haven't even been able to apply roll, pitch and minimal yaw without adjusting throttle so mark all limits as breached
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT | AP_MOTOR_YAW_LIMIT | AP_MOTOR_THROTTLE_LIMIT;
        }

        // if we didn't give all the yaw requested, calculate how much additional yaw we can add
        if( rc_yaw_excess != 0 ) {

            // try for everything
            yaw_to_execute = rc_yaw_excess;

            // loop through motors and reduce as necessary
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] && _yaw_factor[i] != 0 ) {

                    // calculate upper and lower margins for this motor
                    upper_margin = max(0,out_max - motor_out[i]);
                    lower_margin = max(0,motor_out[i] - out_min);

                    // motor is increasing, check upper limit
                    if( rc_yaw_excess > 0 && _yaw_factor[i] > 0 ) {
                        yaw_to_execute = min(yaw_to_execute, upper_margin);
                    }

                    // motor is decreasing, check lower limit
                    if( rc_yaw_excess > 0 && _yaw_factor[i] < 0 ) {
                        yaw_to_execute = min(yaw_to_execute, lower_margin);
                    }

                    // motor is decreasing, check lower limit
                    if( rc_yaw_excess < 0 && _yaw_factor[i] > 0 ) {
                        yaw_to_execute = max(yaw_to_execute, -lower_margin);
                    }

                    // motor is increasing, check upper limit
                    if( rc_yaw_excess < 0 && _yaw_factor[i] < 0 ) {
                        yaw_to_execute = max(yaw_to_execute, -upper_margin);
                    }
                }
            }
            // check yaw_to_execute is reasonable
            if( yaw_to_execute != 0 && ((yaw_to_execute>0 && rc_yaw_excess>0) || (yaw_to_execute<0 && rc_yaw_excess<0)) ) {
                // add the additional yaw
                for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                    if( motor_enabled[i] ) {
                        motor_out[i] += _yaw_factor[i] * yaw_to_execute;
                    }
                }
            }
            // mark yaw limit reached if we didn't get everything we asked for
            if( yaw_to_execute != rc_yaw_excess ) {
                _reached_limit |= AP_MOTOR_YAW_LIMIT;
            }
        }

        // adjust for throttle curve
        if( _throttle_curve_enabled ) {
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] ) {
                    motor_out[i] = _throttle_curve.get_y(motor_out[i]);
                }
            }
        }

        // clip motor output if required (shouldn't be)
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i] = constrain(motor_out[i], out_min, out_max);
            }
        }
    }

	// send output to each motor
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( motor_enabled[i] ) {
			_rc->OutputCh(_motor_to_channel_map[i], motor_out[i]);
		}
	}
}

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_disarmed()
{
	if(_rc_throttle->control_in > 0){
		// we have pushed up the throttle
		// remove safety for auto pilot
		_auto_armed = true;
	}

	// Send minimum values to all motors
	output_min();
}

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_test()
{
	int8_t min_order, max_order;
	int8_t i,j;

	// find min and max orders
	min_order = test_order[0];
	max_order = test_order[0];
	for(i=1; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( test_order[i] < min_order )
			min_order = test_order[i];
		if( test_order[i] > max_order )
			max_order = test_order[i];
	}

	// shut down all motors
	output_min();

	// first delay is longer
	delay(4000);
	
	// loop through all the possible orders spinning any motors that match that description
	for( i=min_order; i<=max_order; i++ ) {
		for( j=0; j<AP_MOTORS_MAX_NUM_MOTORS; j++ ) {
			if( motor_enabled[j] && test_order[j] == i ) {
				// turn on this motor and wait 1/3rd of a second
				_rc->OutputCh(_motor_to_channel_map[j], _rc_throttle->radio_min + 100);
				delay(300);
				_rc->OutputCh(_motor_to_channel_map[j], _rc_throttle->radio_min);
				delay(2000);
			}
		}
	}

	// shut down all motors
	output_min();
}

// add_motor
void AP_MotorsMatrix::add_motor_raw(int8_t motor_num, float roll_fac, float pitch_fac, float yaw_fac, int8_t opposite_motor_num, int8_t testing_order)
{
	// ensure valid motor number is provided
	if( motor_num >= 0 && motor_num < AP_MOTORS_MAX_NUM_MOTORS ) {
	
		// increment number of motors if this motor is being newly motor_enabled
		if( !motor_enabled[motor_num] ) {
			motor_enabled[motor_num] = true;
			_num_motors++;
		}

		// set roll, pitch, thottle factors and opposite motor (for stability patch)
		_roll_factor[motor_num] = roll_fac;
		_pitch_factor[motor_num] = pitch_fac;
		_yaw_factor[motor_num] = yaw_fac;

		// set opposite motor after checking it's somewhat valid
		if( opposite_motor_num == AP_MOTORS_MATRIX_MOTOR_UNDEFINED || (opposite_motor_num >=0 && opposite_motor_num < AP_MOTORS_MAX_NUM_MOTORS) ) {
			opposite_motor[motor_num] = opposite_motor_num;
		}else{
			opposite_motor[motor_num] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
		}

		// set order that motor appears in test
		if( testing_order == AP_MOTORS_MATRIX_ORDER_UNDEFINED ) {
			test_order[motor_num] = motor_num;
		}else{
			test_order[motor_num] = testing_order;
		}
	}
}

// add_motor using just position and prop direction
void AP_MotorsMatrix::add_motor(int8_t motor_num, float angle_degrees, int8_t direction, int8_t opposite_motor_num, int8_t testing_order)
{
	// call raw motor set-up method
	add_motor_raw(
		motor_num,
		cos(radians(angle_degrees + 90)),	// roll factor
		cos(radians(angle_degrees)),		// pitch factor
		(float)direction,					// yaw factor
		opposite_motor_num,
		testing_order);

}

// remove_motor - disabled motor and clears all roll, pitch, throttle factors for this motor
void AP_MotorsMatrix::remove_motor(int8_t motor_num)
{
	int8_t i;

	// ensure valid motor number is provided
	if( motor_num >= 0 && motor_num < AP_MOTORS_MAX_NUM_MOTORS ) {

		// if the motor was enabled decrement the number of motors
		if( motor_enabled[motor_num] )
			_num_motors--;

		// disable the motor, set all factors to zero
		motor_enabled[motor_num] = false;
		_roll_factor[motor_num] = 0;
		_pitch_factor[motor_num] = 0;
		_yaw_factor[motor_num] = 0;
		opposite_motor[motor_num] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
	}

	// if another motor has referred to this motor as it's opposite, remove that reference 
	for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		if( opposite_motor[i] == motor_num )
			opposite_motor[i] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
	}
}

// remove_all_motors - removes all motor definitions
void AP_MotorsMatrix::remove_all_motors()
{
	for( int8_t i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
		remove_motor(i);
	}
	_num_motors = 0;
}
